Combination low water cutoff and pressure control



June 3, 1941. R N NORSTRAND 2,244,131

QOMBINATION LOW WATER CU'IOFF AND PRESSURE CONTROL Filed March 28, 1939o /7 415 o /a J 40 10 Z0 j 2y x M r M.

.1 III III A 'ens' a K a? I J INVENTOR 4m Z VAN A msmw Patented June 3,1941 UNITED STATES PATENT OFFICE COMBINATION LOW WATER CUTOFF ANDPRESSURE CONTROL 8 Claims.

This invention relates to boiler controls, and in its preferredembodiment relates to combined water level and pressure controlleddevices for cutting off the operation of power-actuated devices such asoil burners, forced draft blowers, and the like.

One object of the invention is to provide a combined low water and highpressure cut-off in which the same switch actuating mechanism is usedfor both operations. A further object is to provide a boiler controldevice of this general type in which the float and pressure mechanismsare independent of the angular position in which the carrying frame isattached to the boiler, and in which the control mechanism can beadjusted into its correct angular position after the device is inposition on the boiler. A further object is to provide an improved formof mechanism for preventing false indications of the device by reason ofsurges in the boiler, such mechanism being free from danger of becomingclogged due to the formation of deposits from the boiler water. Afurther object is to provide a device of this general character havinggreat simplicity of construction. Additional objects will appear fromthe following description and claims.

Referring to the drawing,

Fig. 1 is a central longitudinal section through the device, the partsbeing shown in normal or "on position;

Fig. 2 is a similar partial view showing the parts in off position;

Fig. 3 is a section on line 3-3 of Fig. 1;

Fig. 4 is a detail of the control switch, looking from the left in Fig.1;

Fig. 5 is a similar detail, but showing the parts in the "off" position;

Fig. 6 is a section on line 6-6 of Fig. 1; and

Fig. 7 is a section on line 11 of Fig. 6.

The device is supported by a body portion or plug I0, having a screwthreaded portion ll adapted to be screwed into a hole in the side of aboiler, a nut l2 by which it can be rotated, and a chamber I3. A sleeveI4 is held in a central aperture in the plug, as by a press fit, and hasa hole l5 through its center flaring outwardly in a direction externalto the boiler. The inner end of this hole is contracted at I6 to furnishsliding and tilting support for a rod IT. For this purpose the edges ofthe contraction l6 are preferably rounded as shown. The sleeve M has aflange l8 to which is secured one end of a corrugated metal bellows IS,the other end of which is secured to a disk 20 fastened in any suitableway to the float 2!. The bellows serves to furnish a flexible connectionbetween the float and the sleeve l4, whereby the float may move eitherup and down, or toward and away from the sleeve, without permittingleakage between them. The bellows also serves as a pressure controlmeans as will be described.

Rotatably positioned upon the outer end of the sleeve 14 is a controlsupport 25 having a set screw 26 to permit it to be secured in anydesired angular position. Upon a pivot 21 carried by this support is anarm 28 to which a mercury switch 29 of a usual type is held by a clamp30. The rod 57 passes freely through a hole in the arm, so that if therod tilted from the position of Fig. l to that of Fig. 2 the arm will berocked sufliciently to shift the switch from the "on to the oilposition. An insulating strip 3I' is supported on lugs 32 on the support25, and carries binding posts 33 by which the mercury switch may beconnected to the device to be controlled.

It can readily be seen that, with no more mech anism than thatdescribed, the rise and fall of the float in accordance with the levelof the water will cause the rod to tilt in its bearing l6 and rock theswitch-carrying arm 28. Additional mechanism is, however, necessary tocause the switch to be rocked by an increase in pressure in the boiler,which causes the bellows to be contracted. To convert the longitudinalmovement of the rod thus produced into a rocking motion, a linkage isproduced which also has the effect of changing the motion of the rodwhen controlled by water level without, however, varying itseffectiveness. The motion of the rod is identical whether the operatingforce is the sinking of the float or the contraction of the bellows.

To accomplish this result a curved link 35 is pivoted at 36 to a lug onthe support 25, and bends over the end of the sleeve M to engage pintles38 on opposite sides of a sleeve 39 loose on the rod I3. The sleeve 39can be held in ad justed position on the rod by opposed pairs of locknuts 40. The operation of this linkage may be most clearly seen if acompressive force be imagined to be exerted on the right-hand end of thebellows. This causes a sliding of the rod ll to the left, but thelinkage requires that. any such motion be accompanied by a tilting ofthe rod to permit it to follow the curved path of the end of the link.(The link, of course, acts as if it extended straight from the pivot 38to the pivot 36, the former pivot always swinging in an are about thelatter.) The rod pivots about the point 16 as always, causing the floatto be depressed and elevating the arm 28. Lowering the float in thewater requires force, and the float itself thus acts as a resistanceagainst the contraction of the bellows, making the use of springs or ofhigh resilient material for the bellows necessary. In fact, the responseto pressure increase can be to some extent controlled by Varying theshape of the float. It is desirable for purposes of control, however, tohave the bellows made of resilient material so that an initial bias canbe given by the lock nuts it) and the point at which the switch istripped thus varied. The lock nuts thus serve as a pressure control,together with the ability to rotate the support 25 slightly to changethe initial setting of the switch.

When the device is responding to low water the rod goes through exactlythe same motion, pivoting still at the point 16. The natural motion isin this case one of tilting, while the motion enforced by the link 35 isone of sliding. But little resistance to such sliding is interposed bythe bellows, which is always under some compression due to the excess ofpressure inside the boiler. The point at which low water cut-01f isachieved is determined by the position of the device in. the boiler, andis not critical.

It should be particularly noted that the support 25 can be rotated intothe desired angular position after the plug l 0 has been screwed homeinto the hole provided in the boiler wall. This makes it possible torely upon tapering pipe threads to produce a tight fit between the plugand the boiler instead of requiring packing and accurately turnedflanges. The saving of time in installation is very marked. The locknuts M! can also be adjusted after the device is in place,

making it possible to change or adjust the point at which high pressurecut-off occurs.

It is desirable to protect the float from the oscillations produced byrapid surges within the boiler. For this purpose the plug I0 is providedwith a cylinder 4! enclosing the float. The end of this cylinder isbraced as by cross members 42, to the center of which is loosely pivotedat 43 a disk 44. When surges occur the disk swings on its loose pivotand prevents the effect of the surges being felt to their full extentwithin the cylinder. At the same time the slight swinging movement ofthe disk opens and closes the circumferential aperture between it andthe cylinder, and keeps this aperture from becoming plugged due toaccumulations of material deposited from the boiler water.

It will be understood that while the device has been described asextending within the boiler it could equally well be mounted upon thewall of a chamber connected to the boiler so that the conditions to becontrolled are equivalent within the chamber and within the boiler. Theterm within the boiler" is, therefore, used for brevity as covering bothsituations.

I claim:

1. A combined low water and high pressure cut-off comprising a supportsecured to the wall of a boiler, a rod slidably and pivotally supportedin said support, a bellows surrounding the rod and secured thereto so asto make a flexible fluid-tight seal between it and the support, a floatcarried by the rod, means constraining the rod for simultaneous slidingand tilting movement, a switch, means actuated by one of said movementsof the rod for actuating the switch, and a support for said switch andfor said lastnamed means permitting their rotative adjustment withrespect to the rod after the firstnamed support has been secured to thewall of a boiler.

2. A combined low water and high pressure cut-off comprising a supportsecured to the wall of a boiler, a rod slidably and pivotally supportedin said support, a bellows surrounding the rod and secured thereto so asto make a flexible fluid-tight seal between it and the support, a floatcarried by the rod, a link having one end pivoted to the rod and itsother end stationarily pivoted to the support on the outside of theboiler wall whereby sliding and tilting of the rod must occursimultaneously, a switch, and means actuated by one of said movements ofthe rod for actuating the switch.

3. A combined low water and high pressure cut-off comprising a supportsecured to the wall of a boiler, a rod slidably and pivotally supportedin said support, a bellows surrounding the rod and secured thereto so asto make a flexible fluid-tight seal between it and the support, a floatcarried by the rod, a second support adjustable on said first support, alink having one end pivoted to the rod and its other end stationarilypivoted to said second support whereby sliding and tilting of the rodmust occur simultaneously, a switch secured to the second support, andmeans actuated by one of said movements of the rod for actuating theswitch, said second support for said switch and for the stationarilypivoted end of the link permitting their rotative adjustment withrespect to the rod after the first-named support has been secured to thewall of a boiler.

4. A switch actuating device controlled by conditions within a boilercomprising a float, switch means controlled thereby, a cylindersurrounding the float, and a disk pivoted to close the end of thecylinder loosely to permit water to enter and leave the cylinder bytilting the disk.

5. In a switch actuated float control mechanism of the class described,a cylinder surrounding the float, said cylinder being affixed at one endto the switch means and having at the other end means for insuring aquiet flow of liquid in and out of said cylinder, said means consistingof members aflixed to the wall of the cylinder at the open end thereofand extending across said end, and a disk spaced from the end of thecylinder so that liquid may pass through the cir cumferential aperturebetween said disk and the cylinder.

6. In a switch actuated float control mechanism of the class described,a cylinder surrounding the float, said cylinder being aflixed at one endto the switch means and having at the other end means to permit a quietflow in and out of the cylinder, said means consisting of membersaffixed across the open end of said cylinder, a screw fixed in thecenter of the intersection of said members, and a disk loosely pivotedon said screw and covering the end of the cylinder, said disk beingadapted to flap back and forth on the pivot, thereby preventing anysurges due to turbulent forces outside the cylinder from beingtransmitted inside said cylinder, said action of the disk alsopreventing accretion of foreign matter in the circumferential aperturebetween the disk and cylinder.

7. A switch actuating device controlled by conditions Within a boiler,comprising a float, switch means controlled thereby, a cylindersurrounding the float, cross members aflixed to and extending across theopen end of the cylinder, and a disk pivoted on said cross members toopen and close the end of the cylinder loosely by tilting back andforth, all for the purpose described.

8. A combined low water and high pressure cut-off comprising a supportsecured to the wall of a boiler, a rod slidably and pivotally supportedin said support, a bellows surrounding the rod and secured thereto so asto make a flexible fluid-tight seal between it and the support, a floatcarried by the rod, a second support adjustable on said first support, alink having one end pivoted to the rod and its other end stationarilypivoted to said second support whereby sliding and tilting of the rodmust occur simultaneously, a switch secured to the second support, meansactuated by one of said movements of the rod for actuating the switch,said second support for said switch and for the stationarily pivoted endof the link permitting their rotative adjustment with respect to the rodafter the firstnamed support has been secured to the wall of the boiler,a cylinder attached to said firstnamed support and surrounding thefloat, cross members affixed to the wall of the cylinder and extendingacross the open end thereof, and a disk pivoted on said cross members,said disk being adapted to tilt against the end of the cylinder toprevent a turbulent condition within the boiler from affecting the floatinside said cylinder.

RALPH E. VAN NORSTRAND.

CERTIFICATE OF CORRECTION. Patent No. 2,2.M 151. June 5, 191a. RALPH E.VAN NORSTRAND.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 2,first column, line 14-5, for the word "necessary" read unnecessary-;;and that the said Letters Patent should be read with this correctiontherein at the same may conform to the record of the case in the PatentOffice Signed and sealed this 8th day of July, A. D. 19141 Henry VanArsdale, (Seal) Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION. Patent No. 2,2hl 151. June 5, 19m.

Y R LPH E. VAN NORSIRAND.

It is hereby certified that error appears in the printed specificatioilof the above numbered patent requiring correction as follov'x rs: Page2, first 0011111111, l L-5, or the word "necessary" read --unnecessaryard that the said Letters Patent should be read with this correctiontherein at the same may conform to the record of the case in the PatentOffice.

Signed and sealed this 8th day of July, A. D. 1914.1

Henry Van Arsdale, (Seal) Actihg Commissioner of Patents,

